Manufacture of articles from steel alloys



Patented Oct. 11, 1938 2,132,877 MANUFACTURE or narrows mous'ram.

' .umrs

- Friedrich Karl Naumann, Essen, Germany, assignor to Fried. Krupp Aktiengenellscbaft, Essen-on-the-Buhr, Germany No Drawing. Original application November 22,

1933, Serial No. 699,300. Divided and this application October I, 1936, Serial No. 104,437.

- In Germany December "I, 1932 2 Claims. (oi. 75-126) This invention relates to the manufacture ofarticles that by their nature are subjected in use to, and must withstand the attack of hydrogen and gas mixtures containing hydrogen, at high temperatures and high hydrogen partial pressures, such as of apparatus and parts thereof which are used in the destructive hydrogenation of oil and coal, or in the synthesis of ammonia. It is known to make such apparatus and parts thereof from so-called noble alloy steels containing chromium, tungsten, molybdenum or vanadium, and in some cases also nickel.

It is also known in the manufacture of apparatus for cracking oil and tar to make use of steel alloys which contain no nickel, but up to 13% chromium, and which may also contain elements as follows:-

0.3 to 4% aluminum,

0.2 to 2.5% copper,'and Up to 2% of one or more of the elements silicon, moybdenum, vanadium, titanium orberyllium. The present invention is not concerned with the apparatus or parts thereof used in cracking processes but with regard to the treatment of oil and coal only with apparatus in which oil and coal are brought into reaction with hydrogen and the operation is carried on at high hydrogen partial pressures.

According to the present invention use is made for the manufacture of the articles in question of steel alloys which contain titanium and one or more of elementsimproving the creep strength of the alloy, viz. chromium, tungsten, molyb denum and vanadium- Q In my co-pending application for Letters Patent, Serial- Number 699,300 vfiled November 22, 1933, of which the present application is a division, I have shown that titanium possesses to a much greater degree than chromium, tungsten,

I molybdenum and vanadium, the property of makcarbon is bound to the titanium as titanium carbide (TiC).

The addition of one or more of the elements Cr, W, Mo, V has for its object to improve the" creep strength of the steel alloys, since'this property is of great importance for the apparatus,

. four times as great as the carbon content. The

balance of the alloys consists substantially in iron with the normal contents of Mn and Si. The latter content, however, may amount also up to It has been found particularly suitable to make use for the articles mentioned above, of steel alloys which contain-carbon in an amount not exceeding 0.4%, titanium in an amount not exceeding 2%, and molybdenum or vanadium or both in a total amount not exceeding 3%, with or without chromium in an amount not exceeding 10%. For apparatus for the destructive hydrogenation of oil and coal as well as for the synthesis of ammonia the following steel alloys may,

for example, be used:-

1. A steel alloy containing about 0.15% C, 0.23% Si, 0.36% Mn, 0.80% Cr, 0.40% Mo and 0.83% Ti,

2. A steel alloy containing about 0.10% C,

0.50% Si, 0.40% Mn, 0.80% Cr, 2.2% Mo and 3. A steel alloy containing about 0.10% C,

0.30% Si, 0.40% Mn, 0.5-1.0% Mo and 0.50% Ti, 4. A steel alloy containing about 0.10% C, 1.50% Si, 0.50% Mn, 6.0% Cr, 0.40% Mo and 0.50% Ti.

, I claim:

1. Articles which in their normal use are sub- .jected to the attack of hydrogen at high hydrogen partial pressures and high temperatures, said articles being composed of a steel alloy consisting of carbon not over 1%; metal from the group chromium, molybdenum, tungsten and vanadium. toincrease the creep strength, within the limits: up to 10% for chromium and up to 3% molybdenum, tungsten and vanadium; an amount of titanium suflicient to protect the carbon, but not more than 5%; the remalnder'substantially iron with silicon not over about 1.5% and a manganese content within the usual range for low alloy steels.

2. Articles which in their normal use are subjected to the attack of hydrogen at high hydrogen partial pressures and high temperatures, said articles being composed of a steel alloy consisting of carbon not over 0.4%; metal from the group chromium, molybdenum, tungsten and vanadium, to increase the creep strength, within the limits: up to 10% for chromium and up to 3% molybdenum, tungsten and vanadium; ti-

tanium in an amount at least four times greater than the carbon content and not over 2%; the remainder substantially iron with silicon not over about 1.5%. and a manganese content Within the usual range for low alloy steels.

FRIEDRICH KARL NAUMAN N. 

